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61.
62.
Walter Hahn Guy Cellerier Wolfgang Wilhelm Jindra Kulich Robert J. Havighurst Bryan T. Peck Annegret Körner Rodney Skager Renate Nestvogel J. H. Sislian John J. Bergen Peter W. Kahl Tony Bates 《International Review of Education/Internationale Zeitschrift für Erziehungswissenschaft/Revue internationale l'éducation》1978,24(4):523-544
63.
This paper introduces a polynomial operator called the DT-polynomial as a novel approach to network flow problems. The class of networks dealt with is time-varying in the sense that the capacity, cost, and travel-time of each edge may vary in discrete time. The Dt-polynomial is a polynomial in two operators, D (delay) and T (time), which is used for describing the time-varying transmission characteristics. The paper starts with the mathematics involving the DT-polynomials. A new shortest arrival route algorithm is presented, and its computational complexity is found to be favorable in comparison with others such as Dijkstra's method and the potential method derived from Ford-Fulkerson's technique. Furthermore, a dynamic flow problem is formulated and analyzed in terms of DT-polynomials, and a latest-departure earliest-arrival schedule is given. Finally, a modified DT-polynomial is applied to digital filter networks. 相似文献
64.
In an attempt to clarify the chronological relationship between identity and equivalence conservation, normal preschool-aged children (experiment 1) were exposed to brief videotape demonstrations of a model conserving identity and equivalence, identity only, equivalence only, or neither. Subsequent performances indicate that identity was easier to accelerate than equivalence, and training in both identity and equivalence appeared to be most effective in accelerating conservation. Trainable mentally retarded (TMR) children were then exposed to either the identity-equivalence-conserving or control model (experiment 2). This population, which some have argued remains at a preoperational level of functioning, was more likely to conserve identity than equivalence. In addition, conservation in the training group increased following training, though these gains were not maintained over a 3-week retention interval. 相似文献
65.
The reproducibility of microwave integrated circuits can be improved by employing substrates which are anisotropic. A method is presented which facilitates the computation of the characteristics of distributed integrated microwave circuits of finite conductor thickness on anisotropic and inhomogeneous substrates. The method is variational and it relies on a quasi-static approach which assumes that the charge distribution on each side of the conductor can be represented by a spatially dependent set of exponential functions. 相似文献
66.
The behavior of narcotics-addicted and nonaddicted newborns on the first 2 days of life was assessed with the Brazelton Neonatal Behavioral Assessment Scale. In addition to classic signs of narcotics abstinence, addicted infants were less able to be maintained in an alert state and less able to orient to auditory and visual stimuli. These deficits were especially pronounced at 48 hours of age. Addicted infants were as capable of self-quieting and responding to soothing intervention as normal neonates, although they were substantially more irritable. These characteristics and addicted infants' greater resistance to cuddling are discussed in terms of their potential impact on early infant-care-giver interaction. 相似文献
67.
68.
G.K. Wertheim 《Journal of The Franklin Institute》1974,298(4):289-298
The principles of X-ray photoelectron spectroscopy are outlined. The application of this technique to the study of the electronic structure of metals, alloys and compounds is illustrated using data in Ag, β-brass, ReO3 and VO2. In the latter a major change in the density of states is observed on passing through the metal-insulator transition. 相似文献
69.
70.
In this paper, the stability equation method is applied to the analysis of nonlinear systems with characteristics equations having complex coefficients. Three types of systems are studied: those with unstable open-loop poles, unstable characteristics roots or an equal number of open-loop poles and zeros. 相似文献